Process for the preparation of a catalyst



3,132,111 ruocuss sou Tim PuEPAnATIoN or A CATALYST Henry Erickson, ParkForest, and Marvin F. L. Johnson,

Homewood, Ill., and Carl D. Keith, Summit, N..l., assignors, by mesneassignments, to Sinclair Research Inc, New York, N.Y., a corporation ofDelaware No Drawing. Filed Mar. 31, 1960, Ser. No. 18,873

a Claims. (Cl. 252464) searching for an improved catalyst material whichis relatively inexpensive and has high catalyst activity and resistanceto loss in activity over a long processing period. Several methods havebeen suggested for increasing catalyst activity, the strength ofcatalyst particles and their resistance to deterioration. One processfor catalyst imrovemerii' involves double impregnation where a finelydivided catalyst base is impregnated with a promoting metal component,dried, calcined, impregnated again with the catalytic promoting materialand then pelleted prior to recalcination. However, this multipleimpregnation of the catalyst base supplies a product whose catalyticcharacteristics can be improved upon, for instance with respect to thedesulfurization of normally liquid petroleum hydrocarbons. It isdesirable that in certain processes, such as fixed bed desulfurizationprocesses, the catalyst be present as macrosized particles ranging fromabout 5 to /2" in diameter and about 3& to 1" or more in length. A v

In accordance with the present invention, We have found that macrosizecatalysts of the activated alumina base type having deposited thereoncertain metals as catalytically active components, may be greatlyenhanced as to' their hydrocarbon hydrotreating activity and aging staUnited States Patent 0 3,132,111 Patented May 5, 1964 the secondimpregnation. Perhaps the metal gradient so provided is responsible forour unusual result. The catalyst support or base is alumina. In themethod of this invention activated alumina or alumina hydrate,preferably the latter, in small or finely divided form is mixed with anaqueous medium containing the catalytically active metal. As an example,the initial alumina base can be any of the hydrate forms such as themonohydrate, trihydrate or hydrous amorphous alumina; for instance, aneifective catalyst base precursor may comprise up to about 95 oftrihydrate and about 5 to 100% of other hydrous aluminas in the form ofalumina monohydrate, e.g., boehmite, as detected by X-ray analysis afterdrying or in the form of amorphous hydrous alumina or mixtures of theseforms. A preferred base contains about 10 to 50% of the trihydrate andabout 90 to 50% of the amorphous or monohydrate forms. The alumina basecan contain minor amounts usually up to about or of promoting orstabilizing constituents as, for instance, silica, titania, zirconia,thoria, etc.

In each impregnation step the metallic components 7 may be added to thecatalyst support by any procedure desired but usually in both steps anaqueous medium is employed. As an example impregnation may be effectedby the use of an aqueous slurry containing relatively insoluble metalcomponents or an aqueous solution of metal containing Water-solublesalts. The latter type of operation is preferred in our secondimpregnation. The catalytically active components which are deposited onthe alumina base include metals of the ion transition group, i.e.cobalt, nickel and iron; the metals of the fifth and sixth period ofgroup VIb, i.e. molybdenum and tungsten;

vanadium and their various combinations, particularly combinations of aniron transition metal and molybdenum,=tungsten or vanadium. When a metalcombination is employed it may bepresent only in the first imbility byforming macrosize particles from finely divided alumina containing themetals, calcining the formed par ticles, contacting again the calcinedmacro particles with an additional amount of the catalytic active metalsand then recalcining the catalyst. If desired, the catalyst material maybe dried in a separate operation prior to calcining initially and/ orprior to the subsequent calcination. In a preferred embodiment of thisinvention, a finely divided alumina hydrate is contacted with the metalcomponent in an aqueous medium and then formed into macrosizeparticlesby tabletting or extrusion. These particles are then calcined to obtainactivatedalumina, impregnated again with the same or a different aqueousmetal component and then recalcined. Thus, by the process of thisinvention, superior hydrotreating, e.g. 'hydrodesulfurization,hydrofinishing, hydrocracking, etc., catalysts, containing catalyticallyactive metal components are obtained. Although we are not certain of whysuch catalysts should exhibit enhanced characteristics as compared, forinstance with catalysts made by double impregnation prior to formationof themacrosize particles, this result may be due to the distribution ofpromoting metal in the particles. Thus our method seems to provide themetal throughout the catalyst particles as the result of the initialimpregnation and also gives a high metals concentration at the particlesurface due to pregnation with only a single metal being added in thesecond impregnation, or vice versa.

When using an aqueous slurry of the metal component it is believed thatthe small but finite solubility of the substantially water-insolublecompounds of the metals provides effective transfer of the addedcomponent to the base material as X-ray and microscopical inspections ofthe resulting catalysts indicate combination of the catalytically activecomponent With the base apparently through some reaction mechanism. Asthe substantially water- I insoluble salts are usually offered as thecarbonate, oxide or hydroxideundesirable extraneous ions are notintroduced in the catalyst and thus little or no Washing is necessaryafterimpregnation of the base with the catalytically active component.Useable forms of these salts include the bicarbonates, basic carbonatesand hydrated oxides. Thus the catalyst can be made as, for instance, byagitating the alumina base and the substantially waterinsolublecompounds of the catalytically active component in an aqueous medium fora time sufiicient to effect transfer of an effective amount of thecatalytic component to the base.

If desired, the metal component may be a water-soluble salt such as anitrate, molybdate etc. which is contacted in an aqueous solution withthe alumina base until the de sired constituents have been essentiallyabsorbed, interacted with or precipitated on the catalyst base.Frequently, the soluble salt is in the form of a nitrate. Each addedmetal component on the base will be an amount suflicient to afford asubstantial catalytic effect and Will frequently comprise at least about0.5 weight percent, preferably at least about 1 percent, of the catalystand the metal components may be up to about 30 weight percent or more ofthe total catalyst composition. Thus in each impregnation we prefer toadd at least about 0.25%, preferably at least about 0.5%, of the givenmetal component.

Advantageously, the catalyst which is to be treated in accordance withthe present invention can be prepared by agitating the substantiallywater-insoluble inorganic compounds of the catalytically active metalsin an aqueous medium with a spray dried alumina hydrate base precursorfor a time sufiicient to effect deposition on the alumina base of anamount of metal component which aifords a substantially catalyticeffect. The time necessary to give this result can depend upon thematerial being deposited as well as the conditions of agitation such asthe temperature at which the slurry is digested and in general will beat least about ten minutes. While the slurry is digesting, it is stirredand preferably is at a temperature from about 125 F. to about 190 F. orto about 212 F. Higher temperatures even above 212- F. could beemployed, however, no particular advantage is associated with theirutilization which overcomes the necessity for employing superatmosphericpressure to maintain a slurry by keeping the water'in the liquid phase.Lower temperature such as room temperature and somewhat below can alsobe employed. For instance, cobalt and molybdenum are effectivelydeposited on the alumina base when cobalt-carbonate, molybdenum trioxideand the alumina hydrate base are digested at room temperature in theaqueous slurry with agitation for about six hours. After the slurry hasbeen digested for the necessary time period it is filtered to obtain thesolids which are extruded to the desired shape and size. A preferredcatalyst upon extrusion or tabletting may be a macrosize catalyst havinga particle size of about x A to about /2" x 1' with the preferreddimensions being about to 3 x to The catalyst material is then calcined,usually for a period of about 1-10 hours at a temperature from about 850to 1300 F. or more and prior to calcining the catalyst material may bedried, if desired, for a period of from about 3 to 30 hours at atemperature of from 100 F. to 400 F. The calcined macrosize material isthen contacted again with the same or dilferent aqueous metallicconstituents, and recalcined for instance for a period of about 1-10hours at a temperature of from about 850 to 1300 F. If desired, thecatalyst material may again be dried prior to recalcining. v

The catalyst of this invention can beused in a hydrotr'eated processsuch as hydrodesulfurization, hydrofinishing, or hydrocracking ofnormally liquid petroleum feedstocks. In these systems the feedstock maybe contacted with the catalyst "at a temperature from about 600 to 900.F. and at apressure of from about 100 to5000 p.s.i.g. There is usuallyfree hydrogen addition inthe process and if so there is normally ahydrogen recycle rate of from 500 to 10,000 standard cubic ft./barrel offeedstock. The process will normally run at a WHSV of from about .2 to5. The catalyst may be sulfurized prior to being contacted withpetroleum feedstock. The

feedstock is of the general class of hydrocarbon petroleum oils such asnaphthas and gas oils for desulfurization; lubricating oils and kerosenefor hydrotreating; and residuals for hydrocracking.

The following examples will serve to illustrate typical methods ofpreparation of catalytic compositions by. the

improved process of this invention. The catalysts were tested forinitial catalytic activity (VRA) and aging stability (ARA) in acatalytic desulfurization unit in the calcined at 1050 F. for 2.5 hours.

at 1200 F; .90 percent volatile matter, 2.58 percent EXAMTLE 1 1190grams of alumina "hydrate, equivalent to 878 grams of A1 0 (about 25-30%-3H O), were slurried in 6 liters ofwater and then heated to 180 F. 90grams of M00 and 60 grams of cobalt carbonate, equivalent to 32 grams ofC00, were added to the mixture and then slurried for about 3 hours at180 F., filtered and dried at about 230 F. to produce approximately1,000 grams of a finely divided material having 2.5 percent cobalt and 9percent M00 EXAMPLE II 307 grams of the resulting product weremixed with12.28 grams of Sterotex (a tabletting lubricant) and then tabletted'to4; inch macrosize pellets. These tablets were then calcined at 900 F.for 6 hours and then The product had,

cobalt and 9.12 percent of M00 This-product had a virgin relativeactivity of 123 and an accelerated relative activityof 60.

' EXAMPLE III" 228 grams of the, product ofExample I were calcined for 2/2 hours at 1050 F. and then cooled and impregnated with 749 ml. of asolution containing 14.75 grams of Co(NO -6H O and 13.1 grams 4)s 'z 2i'2O to form a product having 3.75 percent cobalt and 13.5 percent M00This product was then blendal with a quantity of Sterotex equal to about4 percent of the composition by weight, pelleted to /s inch x /s inchsize and then calcined at 900 Efor 6 hours and then calcined 'at 1050 F.for 2 /2 hours. The catalyst had 0.3 percent volatile matter at 1200F.,3.74 percentcobalt and 13.3 percent M60 Testing of the catalyst showed avirgin relative activity of 147 and accelerated relative activity of 65.

EXAMPLE IV 122 grams of product of Example II were evacuated for 1 hourin a 28 inch vacuum into which was then introduced 200 ml. of a solutioncontaining 17.3 grams of presence of free hydrogen using as a feedstocka catalytically cracked light cycle oil, under conditions of 760 F., 450p.s.i.g., 8 WHSV and 700 s,c,f, H recycle gas/bbl. The catalysts werecompared with a commercially available CoO-MoO -Al O catalyst which hasa virgin relative activity (VRA) of 100 and an aging stability (ARA) of40.- i

230 F; The constituents were then calcined for 2 /2 hours at 1050 F. Theproduct'analyzed 1.02 percent volatile matter at 1200 F.', 3.74 percentcobalt and 13.3 percent M00 Testing of the catalyst showed a virginrelative activity of 172 and an accelerated relative activity of 78.2.Thus, it is seen from the above examples that the catalyst madeaccording to the process of the present in vention, see Example IV,supplies the petroleum industry with a superior catalyst having improvedinitial catalytic activity (VRA) and also a superior ability to retainits catalyst activity (ARA) when compared with other generally similarcatalyst materials. Thus in Example III an inferior doubly impregnatedcatalyst was prepared, apparently since the'second impregnation precededrather than followed tabletting.

EXAMPLE v 200 grams of a commercial CoO-MoO -Al O catalyst materialprepared by promoting metal impregnation of a finely divided A1 0hydrate, extrusion, drying and calcination and having 2.41 percentcobalt and 8.51 percent -MoO were contacted with a solution containing98.8 g. per liter of Co(NO -6H O and 48.8 g. per liter (NH Mo O -4H Ofor 15 minutes, dried for 20 hours at C. and-then calcined in a mufflefurnace for 2 /2 hours at 1050- F. The product had thefollowingproperties:

VM at 1200" F. 1.36%; Co 3.96%; and M00 12.7%; VRA 155; ARA 76.

EXAMPLE VI 500 grams of the commercial CoO-MoO -Al O catalyst materialof Example V having 2.41 percent cobalt and 8.51 percent M00 werecontacted with a solution containing 98.8 g. per liter of Co(NO -6H Oper liter, drained, dried for 20 hours at 110 C. and then calcined in amufile furnace for 2 /2 hours at1050 F. The prod uct had the followingproperties:

VM at 1200 F. 0.60%; Co 3.94%; and M00 8.66%.

EXAMPLE VII Table l Percent Percent VRA ARA b Co M003 CommercialCOO-MOOa-AlaOa Used in Examples V to VII 2. 41 8. 51 83 47 Example V..3. 96 12. 7 155 76 Example VI 3. 94 8. 66 79 64 Example VII-.. 2. 34 12.4 135 64 Thus, it is seen that, while reimpregnation of the catalystparticles with one metal results in improved VRA and ARA, substantiallybetter VRA and ARA are obtained by using more than one metalconstituent. An increase in ARA seems particularly significant since animprovement in the level of catalyst'activity over a substantial periodof time is indicative of a lasting benefit.

The above examples are illustrative of other catalysts which can be madein our invention. In such preparations nickel carbonate or nitrate canreplace the corresponding cobalt salts and tungsten oxide can be usedinstead of molybdenum trioxide. Also ammonium vanadate can be employedrather than ammonium paramolybdate.

We claim:

1. In a method of preparing alumina-based catalysts containing metalcomponents, the steps comprising contacting fineiy divided alumina withan aqueous catalytic promoting metal component selected from the groupconsisting of metals from the iron transition group, metals from thefifth and sixth periods of group VII; and vanadium, forming macrosizeparticles of about to /2" in diameter and about 1A6" to 1" in lengthfrom the mixture, calcining the macrosize particles, contacting themacrosize particles with an aqueous catalytic promoting metal componentselected from the group consisting of metals from the iron transitiongroup, metals of the fifth and sixth periods of Group VIb and vanadiumand recalcining the macrosize particles.

2. The method of claim 1 wherein the alumina is in hydrate form. 5

3. The method of claim 2 wherein the metal compo nents include cobaltand molybdenum.

4. In a method of preparing alumina-based catalysts containingmetal'components, the steps comprising contacting finely divided aluminahydrate with an aqueous slurry containing a substantiallywater-insoluble catalytic promoting metal component selected from thegroup consisting of metals from the iron transition group, metals of thefifth and sixth period of group VIb and vandium, forming the mixturetomacrosize particles of about to /2" in diameter and about ,4 to 1" inlength, drying the macrosize particles, calcining the macrosizeparticles, contacting the macrosize particles with an aqueous solutioncontaining a catalytic promoting metal component selected from the groupconsisting of metals from the iron transition group, metals from thefifth and sixth periods of groupVIb and vanadium, drying the macrosizeparticles, and calcining the macrosize particles.

5. The .process of claim 4 wherein the metal components include cobaltand molybdenum.

References Cited in the fileof this patent UNITED STATES PATENTS2,687,381 Hendricks Aug. 24, 1954 2,898,308 Teter et al. Aug. 4, 19592,968,634 Nahin Jan. 17,1961 3,016,347 OHara Jan. 9, 1962

1. IN A METHOD OF PREPARING ALUMINA-BASED CATALYST CONTAINING METALCOMPONENTS, THE STEPS COMPRISING CONTACTING FINELY DIVIDED ALUMINA WITHAN AQUEOUS CATALYTIC PROMOTING METAL COMPONENT SELECTED FROM THE GROUPCONSISTING OF METALS FROM THE IRON TRANSITION GROUP, METALS FROM THEFIFTH AND SIXTH PERIODS OF GROUP VIB AND VANADIUM, FORMING MACROSIZEPARTICLES OF ABOUT 1/16" TO 1/2" IN DIAMETER AND ABOUT 1/16" TO 1" INLENGTH FROM THE MIXTURE, CALCINING THE MACROSIZE PARTICLES, CONTACTINGTHE MACROSIZE PARTICLES WITH AN AQUEOUS CATALYTIC PROMOTING METALCOMPONENT SELECTED FROM THE GROUP CONSISTING OF METALS FROM THE IRONTRANSITION GROUP, METALS OF THE FIFTH AND SIXTH PERIODS OF GROUP VIB ANDVANADIUM AND RECALCINING THE MACROSIZE PARTICLES.